Control device



Oct. 5, 1965 B. A. HILLS 3,209,570

CONTROL DEVICE Filed Sept. 28, 1962 2 Sheets-Sheet l fw N 7 i -M L j 'i I Il ,/j l FP f4 /f l f--' I q, /a ff an i /f f@ (ma ff gp Q5 1 /f /4 j if ,f4 jj INVENTOR. y? /Vz//s Oct. 5, 1965 B. A. HILLS 3,209,570

CONTROL DEVICE Filed Sept. 28, 1962 2 Sheets-Sheet 2 ,Digg/Q@ United States Patent O 3,209,570 CONTROL DEVICE Bert A. Hills, Jackson, Mich., assignor to Walker Manufacturing Company, Racine Wis., a corporation of Delaware Filed Sept. 218, 1962, Ser. No. 227,014 9 Claims. (Cl. 72-21) This invention relates to the art of bending tubes or pipes or the like :and more particularly to tube bending apparatus and methods.

One type of tube bending apparatus with which the present invention is capable yof being utilized comprises a reciprocably mounted bending die :and associated pressure dies. Tubing to be bent is supported between the bending die and the pressure dies during a bending operation. The pressure dies are piv-otally mounted for opposite swinging movement :as bending pressures are exerted through the bending die. Back pressure means are associated with the pressure dies to exert back pressure lthrough the tubing being bent. The black pressure means conventionally takes the form of uid cylinders or the like which are connected to the pressure dies. Such apparatus is described in detail in U.S. Patent 2,887,141 issued to B. F. Bower et al., May 19, 1959, the disclosure of which is hereby incorporated herein by reference.

The primary `object of the invention is to provide new and improved means of controlling back pressures during a bending operation to obtain new and improved bending results.

Another object of the invention is to provide a method of bending tubes wherein back pressures are closely controlled to attain maximum results.

The inventive principles are hereinafter disclosed in :detail by reference to an illustrative embodiment of the invention as shown on the accompanying drawings wherein:

FIGURE 1 is a schematic illustration of a tube bending system incorporating the principles of the invention;

FIGURE 2 is .a sectional view taken along the line 2-2 in FIGURE 3;

FIGURE 3 is an enlarged side elevational View, partly in section, of a portion of the apparatus shown in FIG- URE l; and

FIGURE 4 is a side elevational view of an alternative embodiment.

Referring now to FIG. 1, the bending system includes a bending die and a pair of pressure dies 12, 14 which are adapted to cooperatively engage and support a piece of tube for a bending operation. The bending die 10 is conventionally reciprocably mounted and actuable by a fluid pressure means 16. The pressure dies 12, 14 are supported on rotatable sleeves 18, which are adapted to rotate on shafts 21, 22 in opposite directions during downward movement of the pressure die 10 to obtain a wiping action of the pressure dies relative to the tube 15. Backing pressures are applied to the pressure dies by fluid cylinders 24, 26 through connecting rods 28, 30 and fulcrum arms 32, 34 which are iixedly connected to the sleeves 18, 20. In this manner, uid under pressure in the cylinders 24, 26 can exert back pressures against rotative movement of the pressure dies in the directions of the arrows 36, 38.

A iluid control system is associated with the bending mechanism and comprises a reservoir 50 and a pump 52 driven by a motor 54. An outlet passage 55 connects the reservoir to the pump and a passage 56 is provided to convey fluid from the pump to the fluid pressure cylinders 16, 24, 26. A bypass passage 5S having a conventional control valve 60 is provided to return iluid to the reservoir when predetermined pressures in the sys- 3,209,570 Patented Oct. 5, 1965 ICC tem are exceeded. The fluid is alternately delivered from the p-assage 56 to opposite sides of the cylinder 16 through passages 62, 64 by means of a 4-way valve 66. A return passage 68 is provided to convey fluid -back to the reservoir 50. A passage 70 connects the passage 56 to the back pressure cylinders 24, 26 through a control valve 72 and passages 74, 76. In the preferred arrangement, the valve 72 may take the form of any conventional adjustable pressure valve which is suitable for adaptation as lhereinafter described. A bypass passage 78 is controlled by a relief valve 80 to return high pressure Huid to the reservoir.

Referring now to FIG. 3, the pressure control valve 72 includes an adjustable restriction or the like (not shown) which controls flow of fluid from inlet line 70 to outline lines 74, 76. The adjustable restriction is mounted in a casing 81 and is adjustable by control means in the form of a slidably movable, normally outwardly biased, adjusting member 82. Movement of the member 82 in the direction of the arrow 84 is adapted to vary the pressure controlling restriction in the valve and to vary the rate of flow of iluid through the valve from the passage 70. Spring means or the like may be provided to normally bias the member 82 to the position shown in FIG. 3, which may, for example, be a `position of maximum Huid flow through the valve to the cylinders 24, 26.

In order to obtain maximum bending results, an automatic pressure adjusting means is provided to vary the back pressure exerted through the back pressure dies during the different phases of a particular bending operation. To this end, a sleeve 86 may be threadably mounted on the valve casing 80 in coaxial alignment with the member 82 and supporting a pair of brackets 88, 90. An actuating rod extension 92 is slidably supported in a central bore 94 in the sleeve and protrudes outwardly beyond the outer end of the sleeve 86 at 95. The inner end of the sleeve may be provided with an abutment 95 to receive the end of member 82. A control lever is pivotally mounted at 98 on the bracket 88 and has a pin member 100 threadably mounted thereon for axial adjustment to variably position the end portion 102 which is adapted to engage the end of the extension rod 92 as indicated at 104. The pivotally mounted support arm 96 may be provided with a plurality of adjustment holes 105, 108 to permit adjustable positioning of the pivot arm and thereby provide means of varying the length of movement of the end 106 of the pin 100 for a given amount of movement of the support arm about its pivot 98 and for varying the amount of movement of the pin end 106 for a given amount of pressure die movement as hereinafter described in detail.

A bracket 110 is xed in one of the holes 108 and has one end 112 of a control means, such as a Bowden wire arrangement 114, connected thereto. The bracket 90 is provided to support the Bowden wire and a cushion spring element 116 Imay be mounted between the bracket 90 and the bracket 110. The other end 120 of the Bowden wire is fixedly secured to one end of a pivotally mounted lever arm 122 and is supported by a bracket member 124. The lever arm 122 is centrally pivoted at 128 and carries a cam follower 129, such as a roller element at the other end. A cam means, in the 4form of a cam block 130, having an outer cam surface 132 is attached to the rotatable sleeve 18 and is movable therewith. The outer surface may be gradually tapered to obtain a predetermined amount of pivotal movement of the lever 122 for each degree of rotation of the pressure dies. The taper of the surface determines the amount of movement of the lever arm and the amount of adjustment of the valve 72. The exact contour of the cam surface will be determined by the degree of back pressure variation desired and the desired relationship of back pressure to angle of tube bend as determined by pressure die position. The relatively wide angular movement of the arm 32 between its extreme positions, shown in FIG. 3, is converted through the cam and cam follower to a relatively smaller but directly proportional movement of the control rod 82. The sleeve 18 and arm 32 are shown to be pivotally mounted on the shaft 21 and supported in any suitable manner as by a bearing bracket 138.

An alternative embodiment of the present invention is shown in FIGURE 4 wherein the member 82 of the valve 72 is adapted to be actuated by means of a fluid control system comprising spaced fluid motor means, one of which is actuated by movement of t-he bending apparatus to transmit a signal to the other resulting in corresponding movement. A slave cylinder 150 is provided with a piston 151 and a rod 152 which may be suitably connected to the pressure adjusting member 82 or to the extension rod 92. The slave cylinder 150 is connected by a fluid passage 154 to a control cylinder 155 which may be mounted on a por-tion of the machine frame adjacent the bending die 10. In the illustrative arrangement, the control cylinder piston 156 and rod 157 are adjustably connected to a movable portion of the bending apparatus comprising a bracket 158 xed to the movable bending die 10. Movement of the piston rod 157 and piston member 156 in the control cylinder imparts control signals to the slave cylinder through a closed fluid system. Movement of the bending die is directly transmitted into corresponding linear movement of the piston rod 157 and compression of fluid in the cylinder 155 and the fluid system. Compression of the tluid is directly transmitted through the passage 154 to the slave cylinder 150 and results in a corresponding displacement of the piston 151 and the piston rod 152 resulting in variable positioning of the pressure control 82.

`In operation, a iluid such as oil or the like is drawn from the reservoir 50 by the pump 52 and delivered under pressure to the 4-way control valve 66 through the line 56. The system may be set up to operate at a predetermined pressure by bleeding fluid through the bypass line 58 at a suitably adjusted position of the pressure relief valve 60. The 4-way valve 66 is of conventional design and is operable to direct fluid to either the upper or lower ends of the `bending die cylinder 16 through conduits 62, 64. Downward actuation of the bending die 10 during a bending operation causes pivotal movement of the pressure dies 12, 14 `against the back pressure cylinders. The passage means 70 provides a supply of uid under pressure to the adjustable pressure control valve 72. The amount of iluid passing through the pressure control valve 72 is dependent on the position of the pressure dies 12, 14 since the associated control means continuously adjust the valve 72 during and in direct response to movement of the pressure dies. Although only a wire control system and a uid control system have been illustrated, other systems such as an electrical system may be equally well adaptable for use with the present invention.

I have found it desirable to provide a variable back pressure on the pressure dies during a bending operation and to vary the back pressure in accordance with the degree of rotation of the back pressure dies. In the disclosed systems, increases in the degree of bend imparted to the tubing as the bending proceeds results in variations in Huid pressure directed to the cylinders 24, 26 through the valve 72. In this manner, the back pressure being applied to the back pressure dies 12, 14 can be maintained constant throughout a bending cycle, or can be varied throughout a bending cycle, or can be maintained constant through one portion of the bending cycle and varied throughout another portion of the bending cycle as desired.

The pressure exerted on the back pressure dies through the control arms 32, 34 and the piston rods 28, 30 is dependent on the pressure of the iluid delivered to the uid cylinders 24, 26. The pressure of the fluid delivered to the cylinders 24, 26 is dependent on the adjusted setting of the member 82 of the control valve 72. In order to provide variable adjustment throughout all portions of rotation of the pressure dies, the movement of the pressure dies may be directly transmitted into corresponding movement of the member 82 of the valve. Consequently, pressure in the cylinders 24, 26 is simultaneously adjusted by varying the setting of the restriction in the pressure valve 72 as the pressure dies rotate.

The operation of the alternative embodiment shown in FIG. 4 is similar except that the pressure control valve is controlled by movement of the bending die through a hydraulic system. An electrical system might be equally well utilized. Movement of .the bending die is used to obtain varying pressure valve settings by means of reciprocable movement of the piston rod 157 corresponding to movement of the bending die 10. As the bending die 10 is moved downwardly, piston rod 157 is correspondingly moved downwardly within the cylinder 155 to exert forces through the fluid in the line 154 to the cylinder which causes movement of the rod 152 directly proportional to the amount of bending die movement. The increase in pressure in the cylinder 150 results in displacement of the piston rod 152 and corresponding adjustment of the valve control rod 82 as hereinbefore described.

Since the subject invention is capable of alternative uses and may take various forms, it is intended that the appended claims be construed to include variations and changes in the illustrative designs except insofar as limited by the prior art.

What is claimed is:

1. The method of bending a tubular member comprising the steps of applying a bending pressure, applying back pressure in the area of bend, and simultaneously automatically varying the back pressure applied in the area of the bend during the bending operation in accordance with the degree of angularity of bend attained.

2. The method of bending pipe or the like, comprising the steps of applying a bending force to a bend area of the pipe, applying variable backing pressure forces in the area of bend, and automatically simultaneously varying the amount of backing pressure exerted in direct proportion to the amount of bending force applied.

3. A method of controlling a bending operation in a bending machine having a bending die and pivotally mounted pressure dies comprising the steps of applying pressure to a length of tube through said bending die, applying a corresponding backup pressure to said length of tube through said pressure dies, and automatically varying the pressure exerted through said pressure dies in direct proportion to movement of the pressure dies during the bending operation.

4. Apparatus for bending a tube or the like comprising bending die means, back pressure die means, means for actuating said bending die means to form a bend in a length of tube, back pressure means to exert variable back pressure on the length of tube in the area of bend, and automatic back pressure control means eective during a bending operation to simultaneously control the amount of pressure exerted in the area of bend on the length of tube in accordance with the position of the bending apparatus.

5. The apparatus as dened in claim 4 and wherein said back pressure control means comprises a fluid pressure system, cylinder means connected to said back pressure die means, a control valve to control the pressure of fluid in said cylinder means, and control means connecting said valve means and a movable portion of said die means to actuate said valve means in accordance with the angular position of said die means during a bending operation.

6. The apparatus as dened in claim 5, and wherein said control means comprises a mechanical means connected at one end to said control valve and connected at the other end to a movable part of said die means.

'7. The apparatus as defined in claim 6 and wherein said mechanical means comprises a Wire means, one end of said wire means being connected to a pivotally supported arm, said pivotally supported arm having an adjustable pin mounted thereon, a control rod connected to said Valve means, and said pin being located for engagement with said control rod to cause movement thereof in response to movement of said wire means.

8. The apparatus as dened in claim 7 and wherein the other end of said wire means is connected to a pivotally mounted lever, cam follower means provided on said lever, a cam member mounted on a portion of said die means and being movable therewith, said cam follower being engageably supported on said cam member and adapted to impart pivotal movement to said lever during movement of said die means and causing corresponding movement of said pivotally supported arm on said valve means through said wire means.

9. In tube bending apparatus for bending tubes or the like, a movable bending die means, movable back pressure die means, cylinder means connected to said back pressure means to provide backing pressure therefor, a Huid pressure system to deliver fluid to said cylinders, a valve means controlling the delivery of fluid to said cylinders, a valve control means connected to said valve means to control the rate of flow of fluid therethrough, operating means connected to said valve control means, first uid cylinder means connected to said operating means, second uid cylinder means mounted on said bending apparatus, means controllably connecting said first fluid cylinder means to said second fluid cylinder means, and means connecting said bending die and said second fluid cylinder means to cause actuation thereof in response to movements of said bending die so that movement of said bending die causes corresponding movement of said valve control means by variations in pressure in said cylinder means.

References Cited by the Examiner UNITED STATES PATENTS 2,255,985 9/41 Pfauser 153-38 2,464,459 3/49 NeWlon 153-38 CHARLES W. LANHAM, Primary Examiner. 

1. THE METHOD OF BENDING A TUBULAR MEMBER COMPRISING THE STEPS OF APPLYING A BENDING PRESSURE, APPLYING BACK PRESSURE IN THE AREA OF BEND, AND SIMULTANEOUSLY AUTOMATICALLY VARYING THE BACK PRESSURE APPLIED IN THE AREA OF THE BEND DURING THE BENDING OPERATION IN ACCORD ANCE WITH THE DEGREE OF ANGULARITY OF BEND ATTAINED. 